Piezo-electric crystal control system



April 20 1926.

A. H. TAYLOR PIEZO ELECTRIC CRYSTAL CONTROL SYSTEM Filed 001,. 24, 1925 IN VEN TOR.

A TTORNEY Patented Apr. 20, 1926.

UNITED STATES PATENT OFFICE.

ALBERT H. TAYLOR, OF WASHINGTON, DISTRICT OF COLUMBIA, ABSIGNOB 'IO WIRED RADIO, INQ, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

PIEZO-ELEOTRIC CRYSTAL CONTROL SYSTEM.

Application filed October 24, 1925. sci-m1 no. cacao.

To all whom it may concern:

Be it known that I, ALBERT H. TAYLOR, a citizen of the United States, residing at Washington, in the District of Columbia, have invented certain new and useful Improvclnents in a Piezo-Electric Crystal Control System, of which the following is a specification.

My invention relates broadly to radio transmission systems and more particularly to a circuit arrangement for controlling the operation of radio transmission systems.

One of the objects of my invention is to provide a c stal control circuit for electron tube transmitters wherein a relatively large amount of power ma be controlled for the transmission of signals at high efficiency.

Another object of my invention is to provide a crystal control system for maintaining the frequency of a radio transmitting apparatus constant at the same time that increased efliciency is secured in the operation of the transmitter.

Still another object of my invention is to provide a circuit arrangement for operating a plurality of piezo electric crystals in parallel for the control of a large amount of energy at constant frequency and for improving the over-all efficiency of electron tubes which are connected with the piezo electric crystal control circuit.

M invention will be more clearly understoo from the specification hereinafter following by reference to the accompanying drawings, wherein:

Figure 1 is a diagrammatic view illustrating the circuit arrangement of the piezo electric crystals in the control circuit of a radio transmission system; Fig. 2 is a View illustrating the application of the principle of my invention for controlling a relatively large amount of energy at constant fre quency by means of piezo electric crystals; and Fig. 3 is a parallel arrangement of piezo electric crystals for controlling a high power tube or tubes.

The amount of power that can be derived from a transmitting tube operated with piezo electric control is limited by the following facts:

(a) Size of the piezo electric crystal.

(6) Brushing due to high voltage between one of the contact plates and the surface of the crystal.

(0) Excessive crystal vibration which causes mechanical strain,

rystals showing good piezo electric activities are limited in size. This is truebecause the danger of including small flaws in the piezo electric material, or, in the case of quartz commonly used, portions of the crystal which are optical] twinned. In actual practice the cost 0 producing piezo electrlc crystals from quartz with satisfac tory performance, and whose size is greater :han one square inch of surface is relatively arge.

I have therefore developed a piezo electric crystal control circuit where separate piezo electric crystals are synchronized in their operation to directly control a large amount of power output for reducing in any transmitter design the number of necessary stages of power amplification.

Using even very carefully prepared piezo electric crystals it has heretofore been impossible to get a satisfactory output from a -watt tube under piezo electric control without subjecting the crystal to excessive strain, brushing and heatin resulting in its rapid disintegration. Neifiier has 1t been found satisfactory to operate a number of 7% watt tubes in parallel from one crystal. The output directly controlled by the piezo electric crystal has therefore been limited to between 7 and 15 watts according to the frequency. Higher outputs have been obtained but only under conditions involving serious damage to the crystal.

By my present invention Io rate a multiplicity of synchronized crysta s in arallel to control one tube of higher power t an has heretofore normally been controlled with one crystal, or I arrange a multiplicity of piezo electric crystals to control two or more low powered tubes in parallel relation to each other. The crystals are synchronized so that the outputs thereof are integrated to control the electron tube system. By this ar rangement a direct control of a larger amount of energy than has heretofore been possible is secured and a greater over-all elficiency of the tube or tubes so controlled is obtained.

Referring to the drawings in more detail I have illustrated my invention as applied to an electron tube transmitter having a radiating antenna ground system 1--2 including tuning elements 3 and 4. The antenna system may contain a sufficient amount of inductance 5 which may be shunted by a signaling key 6 for throwing the antenna into or out of resonance with the crystal controlled oscillator tube 10 in the roduction of signals. The tube 10 inclu es filament electrode 10, grid electrode 10, and late electrode 10 connecting to an oscilatory output circuit including inductance 8 and variable capacity 7 with the necessary meters V and A arranged in the oscillatory output circuit. A source of plate potential 11 is provided for tube 10 with radio fre quency choke coils 16 disposed in the circuits of the generator 11. A radio frequency by-pass condenser 17 is shunted across the generator 11 in the oscillatory Cl!- cuit. The filament 10 is heated from a source 12 under control of rheostat 14 with radio frequency choke coils 15 disposed in the leads which connect to the filament 10. Two synchronized piezo electric crystals 18 and 19 are arranged to control the oscillating tube 10. The piezo electric crystal 18 is mounted between conductive plates 20 and 21 for-min the terminals for the piezo electric crysta The piezo electric crystal 19 is included between conductive plates 22 and 23 and connected in the input circuit of tube 10. The crystals 18 and 19 are each ground to approximately the same frequency. The de ree of approximation necessary appears to he of the order of 100th of 1%. In order to synchronize the operation of the piezo electric crystals to thereby integrate the energy delivered by each crysta, I provide balancing sensitizing choke coils 24 and 25 in each of the piezo electric crystal circu ts and adjust these to such value that the oscillations from each crystal add and have no tendency to op ose each other. In order to assist the buil ing up of oscillations in the crystal control circuits, I provide a choke coil 26, common to both of the piezo electric crystal circuits, a source of negative potential 28 which is connected in shunt with the piezo electric crystal eircuits,and aradio frequency choke coil 27 POSIl'JIOIIGd IIhSBI'IBS therewith for the purpose of permitting the free oscillation of the piezo electric crystal control circuits at substantiallyno load. I have illustrated a single electron tube 10 for the purpose of describing the invention. This tube 10 has a ower larger than the tube which is norma 1y em loyed with a crystal control circuit. It s ould be understood however that several low power tubes may have their filament, grid and plate electrodes connected in parallel and operated simultaneously from the piezo electric crystal circuit. Instead of the tube 10 operating directly into the antenna as illustrated, a lead may be brought 011' at the tap 9 on inductance 8 to a grid of a power amplifier tube or any of the well-known methods of master crystal.

oscillator and power am lifier circuits may be employed. Any suitable method of keying the transmitter may be em loyed and the arrangement for throwing t e antenna out of tune with respect to the crystal controlled oscillator has been shown for the purpose of illustration only.

In Fig. 2 I have illustrated an arrangement of piezo electric crystals and synchronization choke coils for controlling a plurality of low power tubes havin their electrodes connected in parallel. in electron tube 30 has its electrodes 30", 30, and 30 parallel connected with corresponding electrodes 10, 10 and 10 of tube 10. In order to secure a still greater increase in power from the piezo electric crystal controlled circuit, I may synchronize an additional piezo electric crystal 31 with the synchronized crystals 18 and 19 as shown in Fig. 3. In this case the piezo electric cr stal 31 is positioned between conductive ates 32 and 33 and connected in series witi choke coil 34 forming a path for constant frequency oscillations parallel to the paths formed for the other piezo electric crystals. The'ener from the several piezo electric crystals 1s integrated to deliver a relatively large output to the electron tube system.

By the arrangement of a multiplicity of piezo electric crystals herein, a larger amount of energy can be directly controlled, than has heretofore been possible. The most important advantage arising out of the s nchronized piezo electric crystal operation is that it greatly improves the overall efiiciency of the tube or tubes so controlled.

Measurements taken on two 7 iwatt tubes in parallel controlled by two synchronized crystals showed a ain of thirty-five per cent (35%) in e ciency. In other words, with twice the input energy of the plates of the tubes as compared with one tube, the output circuit, namely the ener represented by the current flowing throu the ammeter A, increased to 2.7 times t e output energy of one tube controlled by one i In other words, doubling the input energy has more than doubled the output energy. When the system is used on a 50-watt tube the increase is still greater. This, because the 50-watt tube, if used under conditions which are safe for the operation of the crystal, is very ineflicientr-a factor of 4 or 5 on output is possible when operating synchronize crystals controlling a 50-watt tube.

My invention may be applied to the circuits of a master oscillator, driver or simple transmitter with or without power amplifier. If power amplifiers are used modulation may be emphiyed by any of the wellknown methods. y reason of the constant frequency characteristics of each of the piezo electric crystals and the tendency for the crystals after once being synchronized to mutually assist in holding the oscillations of one crystal in ste with the oscillations of another crystal, tie constant frequency characteristics of the radio transmission system thus controlled are improved. It will be understood that my invention is applicable to broadcast radio transmitters in both space and wired radio for the transmission of news, music, concerts, lectures and other entertainment.

While I have described my invention in certain preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon the invention are-intended other than are imposed by the scope of the appended claims.

\Vhat I claim and desire to secure by Letters Patent of the United States is as follows 1. A radio transmission system comprising in combination an electron tube oscillator having grid, filament and plate electrodes, input and output circuits interconnecting said electrodes, and a multipllcit of piezo electric crystals electrically sync rpnized for parallel operation connected in said input circuit for controlling the frequency of said electron tube oscillator.

2. A radio transmission system comprising in combination an electron tube oscillator having grid, filament and plate electrodes, input and output circuits interconnecting said electrodes, and a multiplicity of piezo electric crystals each ground at substantially the same frequency, and each independently connected across said input circuit and synchronized in operation for integrating the effect of the oscillations of each of said crystals upon said input circuit.

3. A radio transmission system comprising in combination an electron tube oscillator having grid, filament and plate electrodes, input and output circuits interconnecting said electrodes, and a multiplicity of piezo electric crystals each ground at substantially the same frequency, each of said piezo electric crystals being mounted between a pair of conductive plates with corresponding conductive plates connected to one side of said input circuit and the opposite conductive plates independently con; necting through separate synchronizing coils with the other side of said input circuit whereby the effect of the oscillations produced by each of said piezo electric crystals may be integrated for controlling said electron tube oscillator.

4. A radio transmission system comprising in combination an electron tube oscilla tor having grid filament and plate electrodes, in ut and output circuits interconnecting said electrodes, and a multiplicity of piezo electric crystals each ground at substantially the same frequency, said piezo electric crystals each being mounted between a pair of conductive plates with the corresponding plates on one side of said piezo electric crystals each connected with said filament electrode of said electron tube oscillator and with the opposite conductive plates each independently connected through synchronization coils with the grid electrode of said electron tube oscillator, whereby the effect of the oscillations produced by each of said piezo electric crystals may be integrated for controlling the operation of said electron tube oscillator. 5. A radio transmission system comprismg in combination an electron tube oscillator having grid, filament and plate electrodes, input and output circuits interconnect ng said electrodes, and a multiplicity of piezo electro crystals each ground at substantrally the same frequency, said piezo electric crystals each being mounted between a pair of conductive plates with the correspondmg plates on one side of said piezo electric crystals each connected with said filament electrode of said electron tube oscillator' and with the opposite conductive lator at-constant frequency.

6. A radio transmission system comprising in combination an electron tube oscillator having grid, filament and plate electrodes, 1n ut and output circuits interconnecting said electrodes, and a multiplicity of piezo electric crystals each ground at substantially the same frequency, a pluralit of branch circuits correspondin in num r to the number of said piezo e ectric crystals, means connected in each of said branch circuits for synchronizing the operation of each of said piezo electric crystals, said branch circuits including said piezo electric crystals in parallel with the input circuit of said electron tube oscillator, and means common to said branch circuits for sustaining the oscillations produced by said electron tube oscilator.

7 A radio transmission system comprising in combination an electron tube oscillator having grid, filament and plate electrodes, input and output circuits interconnecting said electrodes, and a multiplicity of piezo electric crystals each ground at substantiall the same frequency, a branch circuit in which each of said iezo electric crystals is connected, a sync lironization coil connected in each of said branch circuits, with said branch circuits parallel connected with said input circuit and an independent coil series connected with said branch circuits for sustaining the oscillations of said piezo electric crystals, whereby the oscillatory efi'ects of each of said piezo electric crystals may be integrated for simultaneously controlling said electron tube oscillator.

8. In a frequency control or stabilizing system for electron tubes, the combination of a multiplicity of electron tubes and piezo electric crystals of substantially the same frequency characteristics, said electron tubes having a common input circuit and said piezo electro crystals each being synchronized to operate into said common input circuit for integrating the effects of said piezo electric crystals upon said common input circuit.

9. In a frequency control or stabilizing system for electron tubes, the combination of a multiplicity of electron tubes and piezo electric crystals of substantially the same frequency characteristics, said electron tubes having a common input circuit and said piezo electric crystals each being independently synchronized to operate into said common input circuit, and means common to all of said piezo electric crystals and connected in series and parallel relation with said input circuit for operating said piezo electric crystals at substantially no load and sustaining said oscillations at the characteristic frequency of said piezo electric crystals.

10. A frequency control system for high frequenc electrical apparatus consisting of a mlultip icity of piezo electric elements operating in synchronism.

11. In a frequency control system for electron tubes the combination of a multiplicity of piezo electric elements operating in synchronism, an electron tube system, and means for integrating the effect of said piezo electric elements on said electron tube system.

12. In a system for controlling alternating currents the combination of a Work circuit, and means for controlling the infiuence of alternatin currents u on said work circuit comprising a multip icity of piezo electric elements operating in synchronism, for integrating the effect of all of said elements upon said work circuit.

13. A frequency control or stabilizing system for electron tubes, the combination of an electron tube system, and a multiplicit of piezo electric elements, means for synchronizing the operation of said piezo electric elements, and means for integrating the effect of the synchronized piezo electric elements upon said electron tube system.

14. A radio transmission system comprising in combination an electron tube system having grid, filament'and plate electrodes, circuits interconnecting said electrodes, a multiplicity of piezo electric elements, each ground at substantially the same fre uency, a circuit interconnecting all of sai piezo electric elements, means in said circuits for synchronizing the operation of said piezo electric elements. and means for making effective upon said electron tube system the oscillations developed by each of said piezo electric elements for controlling the operation of said electron tube system at the frequency of said elements.

ALBERT H. TAYLOR.

I nected with said branch circuits for sustaining the oscillations of said piezo electric crystals, whereby the oscillatory effects of each of said piezo electric crystals may be integrated for simultaneously controlling said electron tube oscillator.

8. In a frequency control or stabilizing system for electron tubes, the combination of a multiplicity of electron tubes and piezo electric crystals of substantially the same frequency characteristics, said electron tubes having a common input circuit and said piezo electro crystals each being synchronized to operate into said common input circuit for integrating the effects of said iezo electric crystals upon said common input circuit.

9. In a frequency control or stabilizing system for electron tubes, the combination of a multiplicity of electron tubes and piezo electric crystals of substantially the same frequency characteristics, said electron tubes having a common input circuit and said piezo electric crystals each being indepen(l ently synchronized to operate into said common input circuit, and means common to all of said piezo electric crystals and connected in series and parallel relation with said input circuit for operating said piezo electric crystals at substantially no load and sustaming said oscillations at the characteristic frequency of said piezo electric crystals.

10. A frequency control system for high frequenc electrical apparatus consisting of a mlultip icity of piezo electric elements operating in synchronism.

11. In a frequency control system for electron tubes the combination of a multiplicity of piezo electric elements operating in synchronism, an electron tube system, and means for integrating the effect of said piezo electric elements on said electron tube system.

12. In a system for controlling alternating currents the combination of a work circuit, and means for controlling the influence of alternating currents u on said work circuit comprising a multip icity of piezo electric elements operating in synchronism, for integrating the effect of all of said elements upon said work circuit.

13. A frequency control or stabilizing system for electron tubes, the combination of an electron tube system, and a multiplicit of piezo electric elements, means for synclironlzing the operation of said piezo electric elements, and means for integrating the effect of the synchronized piezo electric elements upon said electron tube system.

14. A radio transmission system comprising in combination an electron tube system having grid, filament and plate electrodes, circuits interconnecting said electrodes, a multiplicity of piezo electric elements, each ground at substantially the same fre uency, a circuit interconnecting all of sai piezo electric elements, means in said circuits for synchronizing the operation of said piezo electric elements, and means for making effective upon said electron tube system the oscillations develo ed by each of said piezo electric elements or controlling the operation of said electron tube system at the frequency of said elements.

ALBERT H. TAYLOR.

DIBOLAI M ER 1,581,701.-Albert H. Taylor,

Washin ton, D. C. PIEZO-ELECTRIC Cars-ran Con- TROL SYSTEM. Patent dated April 20, 1926. Disclaimer filed May 5, 1933, by

the assignee, Wired Radio, Inc. Hereby enters a a multiplicity of piezo electric elements in synchronism is a motor element.

10. A frequenc of a multiplicity o piezo electric elements 0 11. In a frequency control system for e ectron tubes crating 1n synchromsm.

disclaimer restricting claims 10, 11, 12, and 13, as listed below, to in which no one of the elements operating control system for high frequency electrical apparatus consisting the combination of a multiplicity of piezo electric elements operating in synchronism, an electron tube system, and means for integrating the effect of said piezo electnc elements on said electron tube system.

12. In a system circuit, and means for controll n work circuit comprising a multip chronism, for integrating the effect of all of said elements upon said work circuit.

13. A frequency control or stabilizing system for electron tubes,

and a multiplicity of piezo electric elements, means for of an electron tube system,

for controlling alternating currents the combination of a work the influence of alternating currents upon said city of piezo electric elements operating in synthe combination synchronizin the operation of said piezo electric elements, and means for integrating t e effect of t e synchronized piezo electric elements up .[Qfl'icial Gazette June 6', 1983.]

on said electron tube system.

DISCLAIMER 1,581,701.Albert H. Taylor, Washington, D. C. PIEZO-ELECTRIC CRYSTAL CON- 'IROL SYSTEM. Patent dated April 20, 1926. Disclaimer filed May 5, 1933, by the assignee, Wired Radio, Inc.

Hereby enters a disclaimer restricting claims 10, 11, 12, and 13, as listed below, to a multiplicity of piezo electric elements" in which no one of the elements operating in synchronism is a motor element.

10. A frequenc control system for high frequency electrical apparatus consisting of a multiplicity o piezo electric elements 0 crating in synchronism.

11. In a frequency control system for e ectron tubes the combination of a multiplicity of piezo electric elements operating in synchronism, an electron tube system, and means for integrating the effect of said piezo electric elements on said electron tube system.

"12. In a system for controlling alternating currents the combination of a work circuit, and means for controllin the influence of alternating currents upon said work circuit comprising a multip 'city of piezo electric elements operating in synchronism, for integrating the effect of all of said elements upon said work circuit.

13. A frequency control or stabilizing system for electron tubes, the combination of an electron tube system, and a multiplicity of piezo electric elements, means for synchronizin the operation of said piezo electric elements, and means for integrating t 0 effect of t e synchronized piezo electric elements upon said electron tube system.

.[Qflimhl Gazette June 6', 1933.] 

